// 导出页面为PDF格式
import html2Canvas from 'html2canvas'
import JsPDF from 'jspdf'

export default {
  install (Vue, options) {
    Vue.prototype.getPdf = function () {
      var title = this.htmlTitle
      html2Canvas(document.querySelector('#pdf_content'), {
        useCORS: true, // 允许跨域
        dpi: window.devicePixelRatio * 20, // 将分辨率提高到特定的DPI 提高四倍
        scale: 10, // 按比例增加分辨率
        allowTaint: true
      }).then(function (canvas) {
        const contentWidth = canvas.width
        const contentHeight = canvas.height
        const pageHeight = contentWidth / 592.28 * 841.89
        let leftHeight = contentHeight
        let position = 0
        const imgWidth = 595.28
        const imgHeight = 592.28 / contentWidth * contentHeight
        const pageData = canvas.toDataURL('image/jpeg', 1.0)
        const PDF = new JsPDF('', 'pt', 'a4')
        if (leftHeight < pageHeight) {
          PDF.addImage(pageData, 'JPEG', 0, 0, imgWidth, imgHeight)
        } else {
          while (leftHeight > 0) {
            PDF.addImage(pageData, 'JPEG', 0, position, imgWidth, imgHeight)
            // eslint-disable-next-line no-const-assign
            leftHeight -= pageHeight
            // eslint-disable-next-line no-const-assign
            position -= 841.89
            if (leftHeight > 0) {
              PDF.addPage()
            }
          }
        }
        PDF.save(title + '.pdf')
      }
      )
    }
  }
}
